Soft covered books, such as manuals, textbooks, catalogs and magazines, and hardbound books do not readily lie flat when opened. Such books often suffer a "mousetrap" effect wherein, when the books are opened, they tend to close of their own accord and must be held open by the user or by an artificial device external to the books.
Various modifications of the books or of the pages of the books have been attempted in the past to overcome this "mousetrap" effect. For example, one arrangement, shown in U.S. Pat. No. 1,897,839, uses a score to weaken each page of a book from the head of the page to its foot. This weakening of the pages negates the "mousetrap" effect and allows the book to lie flat when opened. Because the pages have been scored from head to foot, an indentation is visible at the head and foot of each page. The indentations of all of the pages result in a V-shaped line being visible at the top and bottom edges of the book. Had the pages not been spatially shifted, the line would have appeared as a straight line. Other arrangements use perforations instead of scoring. Still other arrangements use a modified spine arrangement such that the spine of the book bends in a concave manner when the book is opened in order to flip the pages in a manner to maintain the book opened.
These arrangements suffer many disadvantages. For example, when the pages are scored or perforated from the head of each page to the foot of each page, the pages of the book can be weakened to the point where they can be accidentally torn from the book. Moreover, as discussed above, a head to foot scoring or series of perforations produces an undesired visible line when the book is viewed along its top and bottom edges. Furthermore, a special spine arrangement is expensive and difficult to construct.